Apparatus for coating material in strand form



April 2, 9 6- w. w. REA ETAL 2,397,622

APPARATUS FOR COATING MATERIAL IN STRAND FORM Filed Dec. 24, 1941 CLEAN/N6 MOLTE 25 FLU/D T/N 0M QF-H p- ZO MOLTL'N T/N lNl EN TORS W. W. REA

J.E.W/L TIP/(l5 Br A TTOR/VEV Patented Apr. 2, 1946 APPARATUS FOR COATING MATERIAL IN STRAND FORM Wilson W.

Rea, Chatham,

and Joseph E.

Wiltrakis, Plainfleld, N. J asslgnors to Western Electric Company, New York, N. Y., a corporation of New York Application December 24, 1941, Serial No. 424,274 13 Claims. (Cl. 9159.4)

This invention relates to apparatus for coatin material in strand form.

In the coating of a strand with a bath of liquid material and particularly in coating a'metal wire by passing it through a bath of molten metal, a chief problem has long been that of removing excess coating material from the strand as it emerges from the coating bath, and many apparatuses and devices have been originated for that purpose. A particular case of this general character, and one having particular problems, is that of effectively coating with metallic tin copper wires for use in telephone cables and apparatus.

An enormous quantity of such tinned wire is used.

for these purposes every year. At the present time, when there is diihculty in procuring sulficient tin for all of the nations varied needs, the

problem becomes pressing of reducing. the coating to the least practicable thiclmess while ensuring its complete continuity. In some cases the ordinarily entirely satisfactory wiping dies of metal are not entirely satisfactory when applied to produce minimum thickness coatings because they may take no account of small inevitable variations of wire diameter and hence tend to produce coatings unnecessarily thick on thinner portions of wire and too thin or even not wholly continuous on thicker portions.

An object of the present invention is to provide coating apparatus for strands which shall be simple and reliable and shall act efliciently to produce on the strand a coating of exceptional thinness but yet wholly continuous and substantially uniformly thick.

With the above and other objects in view, the invention may be embodied in a device for wiping a strand emerging from a bath of liquid coating material, which device comprises means to remove the major portion of the liquid from the strand and a wiping strand passing around the coated strand in one or more coils and advancin continuously longitudinally of itself and transversely to the coated strand to continuously present fresh wiping surfaces, the wiper strand being under adjustable longitudinal tension to control the severity of the wiping action.

Other objects and features of the invention will appear from the following detailed description of one embodiment thereof taken in connection with the accompanying drawing, in which the same reference numerals are applied to identical parts in the several figures and in which Fig. 1 is a diagrammatic view in longitudinal vertical section of an apparatus constructed in accordance with the invention: and

Fig. 2 is a similar view on an enlarged scale of the wiper strand and its associated elements.

The apparatus herein disclosed as an illustrative embodiment of the invention has for its purpose the tin coating of copper wireparticularly, though with slight and obvious modifications it; could well be applied tocoating almost any analogous strand with almost any liquid material. The apparatus comprises a strand supply means, e. g. a reel in, from which the wire 9 to be coated is drawn by a capstan II in the direction indicated by arrows and is wound, after being coated, on 'a take-up means, e. g. a reel l2. Leaving the supply reel lo, the strand 9 (hereinafter called the core or the coated core to avoid confusion with the wiper strand) presses through a cleaning means such as a pickling bath or a bath N of soldering fluid I5. Thence the cleaned core passes through a bath iii of liquid coating material, e. g.

molten tin H. The core is submerged i the molten tin bath by passing under a roller i8. Emerging from the tin, the core passes through a preliminary wiping die l9, preferably a perforated disk of steel or other suitable material, to remove the major portion of the excess tin carried by the core. The coated and partially wiped core submerge in the oil by passing under a block 21 eccentrically pivotally supported at 28. Forward of the pivot 28, the strand 20 and the block 21 restin on the strand are supported by a transverse bar 29. As thus arranged, the strand 20 is more or, less pinched between the block 21 and the bar 29, thus creating resistance to the advance of the strand. Should the pull on the strand increase for any reason, the strand will lift the block a little from the bar and thus diminish the resistance to advance of the strand. Means are provided to adjust the downward pressure of the block. Thus the block itself may be interchangeable for others of greater or less weight; or additional weights may be piled on the block.

From the tank 24, the strand 20 passes in one or more turns 30 around the strand 9 and thence through a fixed guide 3| and between a pair of loosely meshed gears 32 and It. From these sears the strand drops into a container 84, where it piles up and is periodically cut loose and thrown away. The guide 3! may very well be merely a forked member secured to the apparatus frame or support II. The gear 32 is rigidly mounted on a shaft It rotatably supported in the support 38. The gear a is rotatably mounted on a shaft or pin i'l supported in a lever}! pivoted at II on the support 35. An interchangeable weight III on the lever ll makes it possible to adjust the grip of th gears 32 and 33 on the strand 20 passing between them. The shaft 38 and therewith the gear 32 are driven in the sense shown by arrows by any suitable power means not shown.

Back of the wiping Po nt where the turns 30 of the strand 2. coil around the core 8, a perforated support block ll is rigidly mounted. The coated and wiped core l passes directly through the block 4| from the coils III, the coils being prevented from being dragged along by the block.

While the apparatus will work fairly satisfactorily without the block I, the wiri Pressure of the coils is more easily kept constant when the wiping point is held steady by the block. The effective wiping diameter of the coils 30 varies automaticall with variations in the diameter of the core, being free to follow such variations because of the tiltability of the block 21, and being compelled to follow them by the constantly maintained tension in the strand due to the pull of the gears 32 and I3 against the frictional pinch of the members 21 and 29. The coating on the coated and finished wiped strand is. of uniform thickness and varying external diameter; whereas the rigid dies usually used to wipe off the excess coating material produce a coating of uniform external diameter and of thickness varying inversely with the core diameter, The thickness of the coating varies inversely with the severity of the wiping action, which in turn varies with the tension in the strand 2!! at the coils 30.

In some instances also,the die i8 may be disposed with and all the,wiping done by the coils 30, provided only that the core be not run through fast enough to make the wiped of! coating material pile up at the coils II and fall over them upon the wiped portion of the coated core. For this reason also the diameter of the wiper strand 2| will preferably be not materially smaller than the diameter of the core 9. In the particular case selected to illustrate the invention, 1, e. the tinning of copper wire in a bath of molten tin, it is found that a wiper strand of ordinary textile fiber, cotton, wool, or the like, if drawn along by the gears 32 and a at only moderate speed,

will not be charred or damagingly overheated by the hot metals even when the wire is relatively heavy and retains considerable heatduring the brief transit from the molten tin of the bath to the coils 30. However, in other instances, if found necessary, as for example, where iron wire is to be galvanized in a bath of molten zinc, it may be necessary to use for the wiper strand a composite comprising a strand of cotton, linen, or the like, for tensile strength covered with threads or slivers of fibers of asbestos, or a strand of spun glass or mineral fiber. While it is found generally that the use of the oil 25 on the wiper strand is preferable, as conducing to the production of a more uniform, thin, smooth and yet continuous coating, the apparatus will work reasonably satisfactorily in some instances even if the oil be omitted from the tank 2%.

A primary characterizing feature of the invenenemas tion is the use of the tensioned strand 2. in one or more turns or coils it about the core 9 to wip the latter. Unlike any ordinary wiping die whose effective element is a perforated solid member, the tensioned coils ll expand and contract about a core with variations in its diameter and thus the wiping sheet is substantially constant in severity and produces a uniformly thin coatin since the coils act on the core with a yieldingly constrictive wiping .pressure which is substantially uniform both circumferentially and lensitudinally of the core. It is to be noted that this yieldingly constrictive wiping pressure is uniform under variations in diameter of the core. Large diameter portions of the core are not wiped under substantially more severe wiping pressure than are small diameter portions, as is the case where perforated blocks or plugs of rubber are used as wiper dies.

As applied in coating a core with some molten metals, e. g. tin, solder, lead, alloys of these with antimony or bismuth, and the like, it is of interest that because of the continuous advance of the wiper strand 20 longitudinally of itself through the coil or coils 30, it is possible to use the cheap strands or yarns of combustible non mineral textile fibers, cotton, wool, linen, hemp, artificial fiber and the like, for the wiper strand despite its contact with molten metal.

The embodiment disclosed and described is illustrative and may be variously modified without departing from the spirit and scope of the invention which is particularly pointed out and described in the appended claims.

What is .claimed is:

1. In an apparatus for coating a longitudinally advancing core and having means to apply an excess of liquid coating material to the core, means to remove the excess coating material from the core comprising a flexible wiper strand wound in a coil about the advancing excessively coated core, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

2. In an apparatus for coating a longitudinally advancing core and having means to apply an excess of liquid coating material to the core, means to remove the excess coating material from the core comprising a flexible wiper strand wound in a coil about the advancing excessively coated core, means to maintain the coil of the wiper strand stationary in position while the core passes therethrough, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

3. In an apparatus for coating a longitudinally advancing core and having means to apply an excess of liquid coating material to the core, means to remove the excess coating material from the core comprising a flexible wiper strand wound in a coil about the advancing excessively coated core, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core, means to supply lubricating material to the portion of the wiper strand advancing into the coil thereof, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

4. In an apparatus for coating a longitudinally advancing core and having means to apply an excess of liquid coating material to the core, means to remove the excess coating material from the core comprising a flexible wiper strand wound in a coil about the advancing excessively coated core, means to maintain the coil of the wiper strand stationary in position while the core passes therethrough, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core, means to supply lubricating material to the portion of the wiper strand advancing into the coil thereof, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

5. In an apparatus for coating a longitudinally advancing core and having means to apply an excess of liquid coating material to the core, means, to remove the excess coating material from the core comprising a flexible wiper strand wound in a coil about the advancing excessively coated core, means to advance the wiper strand longitudinally of itself'through the coil to present fresh portions thereof to the core, means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly' constrictive wiping effect on the core, and means to adjust thetensioning means to modify the tension.

6. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core, means to remove excess molten coating metal from the core comprising a flexible wiper strand of non-mineral textile fiber wound in a cofl about the advancing excessively coated core, and means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core.

'7. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core. means to remove excess molten coating metal from the core comprising a flexible wiper strand of nonmineral textile fiber wound in a coil about the advancing excessively coated core, means to maintain the coil of the wiper' strand stationary in position while the core passes therethrough, and means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core.

8. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core, means to remove excess molten coating metal from the core comprising a flexible wiper strand of non-mineral textile fiber wound in a coil about the advancing excessively coated core, means to supply lubricating material to the portion of the wiper strand advancing into the coil thereof, and means to advanc the wiper strand longitudinally of itself through he coil to present fresh portions thereof to the core.

9. In an apparatus for coating a longitudinally advancing core with metal and having means to from the core comprising a flexible wiper strand of non-mineral textile fiber wound in a coil about.

the advancing excessively coated core, means to maintain the coil of the wiper strand stationary in position while the core passes therethrough, means to supply lubricating material to the portion of the wiper strand advancing into the coil thereof, and means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core.

10. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core, means to remove excess molten coating metal from the core comprising a flexible wiper strand of non-mineral textile fiber wound in a coil about the advancing excessively coated core, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

11. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core, means to remove excess molten coating metal from the core comprising a flexible wiper, strand of non-mineral textile fiber wound in a coil about the advancing excessively coated core, means to maintain the coil of the wiper strand stationary in position while the core passes therethrough, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions. thereof to the core, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

12. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core, means to remove excess molten coating metal from the core comprising a flexible wiper strand of non-mineral textile fiber wound in a coil about the advancing excessively coated core, means to supply lubricating material to the portion of the wiper strand advancing into the coil thereof, means to advance the wiper strand longitudinally of itself through the coil to present fresh portions thereof to the core, and means to yieldingly tension the wiper strand throughout the coil thereof to exert asubstantially constant yieldingly constrictive wiping eifect onthe core.

13. In an apparatus for coating a longitudinally advancing core with metal and having means to apply an excess of molten metal to the core, means to remove excess molten coating metal from the core comprising a flexible wiper strand of non-mineral textile fiber wound in a coil about the advancing excessively coated core, means to maintain the coil of the wiper strand stationary in position while the core passes therethrough, means to'supply lubricating material to the portion of the wiper strandadvancing into the coil thereof, means to advance the wiper strand 1ongitudinally of itself through the coil to present fresh portions thereof to the core, and means to yieldingly tension the wiper strand throughout the coil thereof to exert a substantially constant yieldingly constrictive wiping effect on the core.

Certificate of Correction Patent No. 2,397,622. v April 2, 1946.

WILSON W. REA ET AL.

It is hereby certified that the name of the assignee in the above numbered atent was erroneously described and specified as Western Electric Company, w ereas said name should have been described and specified as Western Electra: Company, Incorporated, as shown by the record of assignments in this oflice, and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 16th day of July, A. D. 1946.

[smn] LESLIE FRAZER,

First Assistant Commissioner of Patents. I 

